Demo Data from SIGIR 2026 / reviewers in the wild / expert
Christos Koutras
dblp:201/1395
· DBLP profile ↗
10ranked-venue papers
4as first author
9since 2021 · last 2026
—ORCID · conflict
Domains — the database's venue-derived domains; a paper can count in several
Databases, data management, data science and information retrieval · 8 · 3 first-author · 7 since 2021Graphics, computer vision, multimedia, augmented reality and games · 1 · 1 since 2021Applied, interdisciplinary, general and emerging computing · 1 · 1 first-author · 1 since 2021
Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.
| Databases, data mining, and information retrieval
6 papers |
Data integration and cleaning · 82% Distributed and cloud data management · 10% Machine learning and data management · 8% | |
| Computer graphics and multimedia
1 paper |
Visualization and visual analytics · 100% | |
| Artificial intelligence
1 paper |
Graph learning · 100% |
Topics — the 9 heaviest of 10, each with the papers that count most for it
| Topic | Weight | Papers | Last | Evidence papers |
|---|---|---|---|---|
Data integration and cleaning
schema matching |
2.2 | 4 | 2026 | OmniMatch: Joinability Discovery in Data Products · Proc. VLDB Endow. 2025 Valentine in Action: Matching Tabular Data at Scale · Proc. VLDB Endow. 2021 Valentine: Evaluating Matching Techniques for Dataset Discovery · ICDE 2021 |
Data integration and cleaning
data discovery |
1.4 | 2 | 2025 | OmniMatch: Joinability Discovery in Data Products · Proc. VLDB Endow. 2025 Valentine in Action: Matching Tabular Data at Scale · Proc. VLDB Endow. 2021 |
Data integration and cleaning › data discovery
dataset discovery |
1.0 | 2 | 2021 | Valentine in Action: Matching Tabular Data at Scale · Proc. VLDB Endow. 2021 Valentine: Evaluating Matching Techniques for Dataset Discovery · ICDE 2021 |
Visualization and visual analytics › visual analytics
visual analytics system |
1.0 | 1 | 2026 | BDIViz: An Interactive Visualization System for Biomedical Schema Matching with LLM-Powered Validation · IEEE Trans. Vis. Comput. Graph. 2026 |
Distributed and cloud data management
data lake |
0.8 | 2 | 2023 | Data Lakes: A Survey of Functions and Systems · IEEE Trans. Knowl. Data Eng. 2023 Valentine in Action: Matching Tabular Data at Scale · Proc. VLDB Endow. 2021 |
Machine learning and data management › privacy-preserving machine learning
federated learning |
0.7 | 1 | 2023 | Amalur: Data Integration Meets Machine Learning · ICDE 2023 |
Machine learning › Graph learning
graph neural network |
0.3 | 1 | 2025 | OmniMatch: Joinability Discovery in Data Products · Proc. VLDB Endow. 2025 |
Machine learning › Graph learning
graph self-supervised learning |
0.3 | 1 | 2025 | OmniMatch: Joinability Discovery in Data Products · Proc. VLDB Endow. 2025 |
Data integration and cleaning
metadata management |
0.2 | 1 | 2023 | Amalur: Data Integration Meets Machine Learning · ICDE 2023 |
Methods — techniques the papers use, named apart from their topics
large language model validation · 2.0ensemble matching · 2.0negative example generation · 1.7graph neural network · 1.7survey · 0.7feature augmentation · 0.7factorized learning · 0.7data integration techniques · 0.7schema matching · 0.5dataset fabrication · 0.5
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | BDIViz: An Interactive Visualization System for Biomedical Schema Matching with LLM-Powered ValidationabstractBiomedical data harmonization is essential for enabling exploratory analyses and meta-studies, but the process of schema matching-identifying semantic correspondences between elements of disparate datasets (schemas)-remains a labor-intensive and error-prone task. Even state-of-the-art automated methods often yield low accuracy when applied to biomedical schemas due to the large number of attributes and nuanced semantic differences between them. We present BDIViz, a novel visual analytics system designed to streamline the schema matching process for biomedical data. Through formative studies with domain experts, we identified key requirements for an effective solution and developed interactive visualization techniques that address both scalability challenges and semantic ambiguity. BDIViz employs an ensemble approach that combines multiple matching methods with LLM-based validation, summarizes matches through interactive heatmaps, and provides coordinated views that enable users to quickly compare attributes and their values. Our method-agnostic design allows the system to integrate various schema matching algorithms and adapt to application-specific needs. Through two biomedical case studies and a within-subject user study with domain experts, we demonstrate that BDIViz significantly improves matching accuracy while reducing cognitive load and curation time compared to baseline approaches. Eden Wu, Dishita G. Turakhia, Guande Wu, Christos Koutras, Sarah Keegan, Wenke Liu, Beata Szeitz, David Fenyö, Cláudio T. Silva, Juliana Freire |
IEEE Trans. Vis. Comput. Graph. | 4 |
| 2025 | Characterization of spine and torso stiffness via differentiable biomechanicsabstractWe present a methodology to personalize the stiffness response of a biomechanical model of the torso and the spine. In high contrast to previous work, the proposed methodology uses controlled force–deformation data that mimic the conditions of spinal bracing for scoliosis, which leads to personalized biomechanical models that are suitable for computational brace design. The novel methodology relies on several technical contributions. First, a prototype system that includes controlled force measurement and low-dose radiographs, with low-encumbrance for its implementation in the clinical protocol. Second, a model of differentiable biomechanics of the torso and the spine, which becomes the key building block for robust parameter estimation. And third, an optimization procedure for parameter estimation from force–deformation data, which relies on differentiability of the biomechanics and the image generation process. We demonstrate the application of the methodology to a cohort of 7 subjects who underwent scoliosis check-ups, and we show quantitative validation of the estimated personalized parameters and the improvement over default parameters from the bibliography. • Personalized stiffness estimation of the spine and torso biomechanics. • Prototype for measurement of force–deformation data of the spine. • Differentiable biomechanics model of the torso and spine. • Image-based optimization algorithm for parameter estimation. Christos Koutras, Hamed Shayestehpour, Jesús Pérez 0003, Christian Wong, John Rasmussen, Miguel A. Otaduy |
Medical Image Anal. | 1 |
| 2025 | OmniMatch: Joinability Discovery in Data ProductsabstractWe propose OmniMatch , a novel joinability discovery technique, specifically tailored for the needs of data products : cohesive curated collections of tabular datasets. OmniMatch combines multiple column-pair similarity measures leveraging self-supervised Graph Neural Networks (GNNs). OmniMatch 's GNN captures column relatedness by leveraging graph neighborhood information, significantly improving the recall of joinability discovery tasks. At the same time, OmniMatch increases its precision by augmenting its training data with negative column join examples through an automated negative example generation process. Compared to the state-of-the-art, OmniMatch exhibits up to 14% higher effectiveness in F1 score and AUC without relying on individual, user-provided thresholds for each similarity metric. Christos Koutras, Jiani Zhang 0003, Xiao Qin 0003, Chuan Lei, Vassilis N. Ioannidis, Christos Faloutsos, George Karypis, Asterios Katsifodimos |
Proc. VLDB Endow. | 1 |
| 2024 | Data Lakes: A Survey of Functions and Systems (Extended abstract)abstractData lakes are becoming increasingly prevalent for big data management and data analytics. In contrast to traditional ‘schema-on-write’ approaches such as data warehouses, data lakes are repositories storing raw data in its original formats and providing a common access interface. Despite the strong interest raised from both academia and industry, there is a large body of ambiguity regarding the definition, functions and available technologies for data lakes. A complete, coherent picture of data lake challenges and solutions is still missing. This survey reviews the development, architectures, and systems of data lakes. We provide a comprehensive overview of research questions for designing and building data lakes. We classify the existing approaches and systems based on their provided functions for data lakes, which makes this survey a useful technical reference for designing, implementing and deploying data lakes. We hope that the thorough comparison of existing solutions and the discussion of open research challenges in this survey will motivate the future development of data lake research and practice. Rihan Hai 0001, Christos Koutras, Christoph Quix, Matthias Jarke |
ICDE | 2 |
| 2023 | Amalur: Data Integration Meets Machine LearningabstractMachine learning (ML) training data is often scattered across disparate collections of datasets, called data silos. This fragmentation poses a major challenge for data-intensive ML applications: integrating and transforming data residing in different sources demand a lot of manual work and computational resources. With data privacy and security constraints, data often cannot leave the premises of data silos, hence model training should proceed in a decentralized manner. In this work, we present a vision of how to bridge the traditional data integration (DI) techniques with the requirements of modern machine learning. We explore the possibilities of utilizing metadata obtained from data integration processes for improving the effectiveness and efficiency of ML models. Towards this direction, we analyze two common use cases over data silos, feature augmentation and federated learning. Bringing data integration and machine learning together, we highlight new research opportunities from the aspects of systems, representations, factorized learning and federated learning. Rihan Hai 0001, Christos Koutras, Andra Ionescu, Jessie van Schijndel, Yan Kang 0001, Asterios Katsifodimos |
ICDE | 2 |
| 2023 | Data Lakes: A Survey of Functions and SystemsabstractData lakes are becoming increasingly prevalent for big data management and data analytics. In contrast to traditional ‘schema-on-write’ approaches such as data warehouses, data lakes are repositories storing raw data in its original formats and providing a common access interface. Despite the strong interest raised from both academia and industry, there is a large body of ambiguity regarding the definition, functions and available technologies for data lakes. A complete, coherent picture of data lake challenges and solutions is still missing. This survey reviews the development, architectures, and systems of data lakes. We provide a comprehensive overview of research questions for designing and building data lakes. We classify the existing approaches and systems based on their provided functions for data lakes, which makes this survey a useful technical reference for designing, implementing and deploying data lakes. We hope that the thorough comparison of existing solutions and the discussion of open research challenges in this survey will motivate the future development of data lake research and practice. Rihan Hai 0001, Christos Koutras, Christoph Quix, Matthias Jarke |
IEEE Trans. Knowl. Data Eng. | 2 |
| 2022 | Amalur: Next-generation Data Integration in Data Lakes
Rihan Hai 0001, Christos Koutras, Andra Ionescu, Asterios Katsifodimos |
CIDR | 2 |
| 2021 | Valentine: Evaluating Matching Techniques for Dataset DiscoveryabstractData scientists today search large data lakes to discover and integrate datasets. In order to bring together disparate data sources, dataset discovery methods rely on some form of schema matching: the process of establishing correspondences between datasets. Traditionally, schema matching has been used to find matching pairs of columns between a source and a target schema. However, the use of schema matching in dataset discovery methods differs from its original use. Nowadays schema matching serves as a building block for indicating and ranking inter-dataset relationships. Surprisingly, although a discovery method's success relies highly on the quality of the underlying matching algorithms, the latest discovery methods employ existing schema matching algorithms in an ad-hoc fashion due to the lack of openly-available datasets with ground truth, reference method implementations, and evaluation metrics.In this paper, we aim to rectify the problem of evaluating the effectiveness and efficiency of schema matching methods for the specific needs of dataset discovery. To this end, we propose Valentine, an extensible open-source experiment suite to execute and organize large-scale automated matching experiments on tabular data. Valentine includes implementations of seminal schema matching methods that we either implemented from scratch (due to absence of open source code) or imported from open repositories. The contributions of Valentine are: i) the definition of four schema matching scenarios as encountered in dataset discovery methods, ii) a principled dataset fabrication process tailored to the scope of dataset discovery methods and iii) the most comprehensive evaluation of schema matching techniques to date, offering insight on the strengths and weaknesses of existing techniques, that can serve as a guide for employing schema matching in future dataset discovery methods. Christos Koutras, Georgios Siachamis 0001, Andra Ionescu, Kyriakos Psarakis, Jerry Brons, Marios Fragkoulis, Christoph Lofi, Angela Bonifati, Asterios Katsifodimos |
ICDE | 1 |
| 2021 | Valentine in Action: Matching Tabular Data at ScaleabstractCapturing relationships among heterogeneous datasets in large data lakes - traditionally termed schema matching - is one of the most challenging problems that corporations and institutions face nowadays. Discovering and integrating datasets heavily relies on the effectiveness of the schema matching methods in use. However, despite the wealth of research, evaluation of schema matching methods is still a daunting task: there is a lack of openly-available datasets with ground truth, reference method implementations, and comprehensible GUIs that would facilitate development of both novel state-of-the-art schema matching techniques and novel data discovery methods. Our recently proposed Valentine is the first system to offer an open-source experiment suite to organize, execute and orchestrate large-scale matching experiments. In this demonstration we present its functionalities and enhancements: i) a scalable system, with a user-centric GUI, that enables the fabrication of datasets and the evaluation of matching methods on schema matching scenarios tailored to the scope of tabular dataset discovery, ii) a scalable holistic matching system that can receive tabular datasets from heterogeneous sources and provide with similarity scores among their columns, in order to facilitate modern procedures in data lakes, such as dataset discovery. Christos Koutras, Kyriakos Psarakis, Georgios Siachamis 0001, Andra Ionescu, Marios Fragkoulis, Angela Bonifati, Asterios Katsifodimos |
Proc. VLDB Endow. | 1 |
| 2017 | Probabilistic k-Nearest Neighbor Monitoring of Moving GaussiansabstractWe consider a centralized server that receives streaming updates from numerous moving objects regarding their current whereabouts. However, each object always relays its location cloaked into a broader uncertainty region under a Bivariate Gaussian model of varying densities. We wish to monitor a large number of continuous queries, each seeking k objects nearest to its own focal point with likelihood above a given threshold, e.g., "which of my friends are currently the k = 3 closest to our preferred cafe with probability over 75%". Since an exhaustive evaluation would be prohibitive, we develop heuristics based on spatial and probabilistic properties of the uncertainty model, and promptly issue approximate, yet reliable answers with confidence margins. We conducted a comprehensive empirical study to assess the performance and response quality of the proposed methodology, confirming that it can efficiently cope with large numbers of moving Gaussian objects under fluctuating uncertainty conditions, while also offering timely response with tolerable error to multiple queries of varying specifications. Kostas Patroumpas, Christos Koutras |
SSDBM | 2 |